tirascam astamah sargah

 so ’stavimsad-vidho matah

avido bhuri-tamaso

 ghrana-jña hrdy avedinah

 

Translation by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 

 

The eighth creation is that of the lower species of life, and they are of different varieties, numbering twenty-eight. They are all extensively foolish and ignorant. They know their desirables by smell, but are unable to remember anything within the heart.

 

Purport by His Divine Grace A. C. Bhaktivedanta Swami Srila Prabhupada: 

 

In the Vedas the symptoms of the lower animals are described as follows: athetaresam pasunah asanapipase evabhivijñanam na vijñatam vadanti na vijñatam pasyanti na viduh svastanam na lokalokav iti; yad va, bhuri-tamaso bahu-rusah ghranenaiva jananti hrdyam prati svapriyam vastv eva vindanti bhojana-sayanady-artham grhnanti. “Lower animals have knowledge only of their hunger and thirst. They have no acquired knowledge, no vision. Their behavior exhibits no dependence on formalities. Extensively ignorant, they can know their desirables only by smell, and by such intelligence only can they understand what is favorable and unfavorable. Their knowledge is concerned only with eating and sleeping.” Therefore, even the most ferocious lower animals, such as tigers, can be tamed simply by regularly supplying meals and accommodations for sleeping. Only snakes cannot be tamed by such an arrangement.